Natural killer T (NKT) cells and regulatory T cells (Tregs)are both found within the liver and are known to exhibit immune regulatory functions. Hepatic NKT cells are activated early during inflammatory responses and release cytokines, including interferon gamma (IFN-␥), which we speculated could regulate Treg recruitment to the liver. To examine this, we treated C57BL/6 mice with a specific NKT cell activating ligand ␣ galactosyl-C18-ceramide (␣Gal-C18-Cer) and examined the hepatic recruitment of Tregs. We found a time-dependant increase in the hepatic recruitment of Tregs after NKT cell activation, which was absent in NKT cell-deficient mice. Most recruited Tregs expressed interleukin (IL) 10, and to a lesser extent transforming growth factor beta (TGF-␤). Because IFN-␥ induces the production of chemokine (C-X-C motif) ligand 10 (CXCL10), and Tregs can express the cognate receptor for CXCL10 (that is, CXCR3), we considered that CXCL10 might mediate the hepatic recruitment of Tregs after NKT cell activation. Hepatic CXCL10 levels were markedly increased after ␣Gal-C18-Cer administration in wild-type but not in NKT celldeficient mice. Moreover, approximately 50% of Tregs recruited to the liver after ␣Gal-C18-Cer administration expressed CXCR3 and CXCR3؉ Treg recruitment into the liver was significantly inhibited in IFN-␥ KO mice, and after CXCL10 neutralization. In addition, prevention of CXCR3؉ Treg recruitment into the liver enhanced inflammatory effector cell recruitment into the liver after ␣Gal-C18-Cer treatment. Conclusion: These results show that activated NKT cells can induce the hepatic recruitment of Tregs through a cytokine-tochemokine pathway, which could be relevant in the development of chemokine blocking or NKT cell activating strategies to treat liver diseases.

Plant basic leucine zipper (bZIP) proteins play an essential role in the genes expression and regulation in higher plants. They have been shown to regulate diverse plant specific phenomena, including germination, floral induction and development, seed maturation, photomorphogenesis, biotic and abiotic stresses. Resistance response mediated by the rice blast resistance gene Pi36 is a typical signal transduction, in which 12 OsbZIP genes were differentially expressed by microarray analyses. To understand the potential function of OsbZIP genes during the defense responses against rice blast, the expression analysis of these OsbZIP genes, in response to the blast fungus inoculation and the related defense signal molecules induction, were further conducted using real-time fluorescent quantitative polymerase chain reaction (PCR) technique. Our data indicates that among the 12 OsbZIP genes, the expression level eight tested genes were differentially regulated and maintained to 96 h points post inoculation in rice resistant and susceptible cultivars during Magnaporthe oryzae infection, and all of them were also significantly up-regulated by one or several kinds of exogenous plant hormones stresses. Although, these genes were induced only at early time points (1 to 24 h); it is evident that the OsbZIP genes may be involved in different signaling pathway, and play potential important functions in the defense response to rice blast.

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